Deep space exploration

Deep space exploration will require artificial gravity

Long stays in space have a major hitch. Medical studies of the effects of microgravity on astronauts after several months in low Earth orbit (LEO) cannot circumvent a hard truth — humans are not made to live without gravity. Thus, artificial gravity habitats are now discussed as a crucial part of long-duration near-Earth asteroid (NEA) mining missions.

Artificial gravity will be especially important for multi-year commercial missions where real-time telerobotics will need to be performed by crews housed near the asteroid itself. Such gravity habitats would also be useful for years of exploration of low-gravity bodies such as the Moon,

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or possibly even the moons of the outer planets.

William Kemp, a Washington, DC-area defense contractor, believes he and his business partner, Ted Maziejka, have come up with a design that offers a viable solution in such cases. It is a cylindrical space station 30 meters in diameter, capable of creating variable artificial gravity by rotating the cylinder around its longitudinal axis.

“If we want to stay in space for more than a year we’re going to have to have artificial gravity systems or else we’re going to sacrifice people in the process,” Kemp, founder and CEO of United Space Structures in Falls Church, Va., told Forbes.

For more than three decades, Kemp has been working to perfect its ideas. The company is currently design patent pending and is seeking funding and other partners for what would be a multi-billion dollar investment.

The idea is that artificial gravity is achieved through centrifugal force which requires rotation to create downward pressure. A small 10-meter structure could, in theory, spin fast enough for humans to feel gravity, but Kemp says astronauts using such a structure would have horrible inner ear problems as a result.

“If the rotational speed was too great, your sense of balance would be disturbed and you would soon be on your hands and knees violently ill,” Kemp said.

However, a small cylindrical-shaped station 30 meters in diameter, of the type proposed by Kemp, would create a gravity of 0.6; the minimum necessary to keep humans safely in a gravitational environment for at least two years. The astronauts would live both inside the cylinder and in the semi-hemisphere of the structure.

Kemp indicates that a cylindrical station 30 meters in diameter would require a rotational speed of 5.98 revolutions per minute and that this is the minimum useful size to create artificial gravity. A faster rotation speed would be too uncomfortable for the astronauts.

“The direction of the rotating cylinder is not important,” Kemp said. “Speed ​​is based on the radius of the spinning object and the gravity you’re trying to achieve; the larger the radius; the slower the speed of rotation.

The first step in United Space Structures’ foray into artificial gravity would be to test a 30-meter cylindrical prototype of the system in low Earth orbit, Kemp says. Although such a 30-meter-diameter station would house fewer than 30 people, he says it would also work well for a near-Earth asteroid mining operation in deep space.

As for the potential partners to build these new gravity stations?

“We’re talking to companies like Deep Space Industries that want to mine asteroids and other companies that want to mine the moon,” Kemp said. “We would like to use Space X’s launch pads, but it will all come down to cost, which is why we will initially use composite materials for the structure instead of metals.”

And despite the predicted leaps in space medicine over the next two decades, Kemp is absolutely convinced that there will always be a need for artificial gravity. As he notes, over time, microgravity reduces muscle and bone mass; compresses the optic nerve creating vision problems; dramatically lowers an astronaut’s natural immune system; and can even hamper critical thinking.

But artificial gravity would by no means be a panacea.

In an artificial gravity environment, astronauts would always be aware that they were on a rotating surface, Kemp explains. Walk with the spin, he says, and the effect would be a bit like walking downhill because the ground is falling. Walk opposite the rotation, and it would be a bit like walking uphill because Kemp says the ground would go up. And if you walk perpendicular to the rotation in either direction, he says, you’ll feel like you’re falling slightly to the side.

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